Electric fitting.



1. (mais L E.1. KNA'UFF.

ELECTRIC FITTING.

A'PPLlcAnoN FILED AUG.29. 1911. l

19301954@ Patented Apr. 22,1919.

' ,zfgg

NIHIIIIIII In ver, borg.'

'Aj/W Y bile.

burru sauras rafruur ouurou,

JUtIUs o. nrs arm Entrano I. manera, or CHICAGO, ILLINOIS.

ELECTRIC FITTING.

Specication of Letters Patent.

rammen am'. e2, raie.

Application led August 29, 1917. I Serial No. 188,713.

To all whom it may concern:

Be it known that We JULIUS O. E1s and EDWARD J. KNAUFF, both citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Fittings; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

ln its general as ects, our joint invention relates to electric gttings and aims to provide simple, convenient and cheap means for affording electrical connections between portions of electric ttings in one of which the circuit is grounded to a shell or casing. More particularly, our invention relates to a connecting plug or coupling member :tor use with a socket having circuit terminals formed respectively by a metal shell and by a contact member insulated from this shell, and having its shell equipped with means for interlocking with a portion of the plug or coupling member. For example, in locating automobile troubles or lighting the interior of the radiator casing for any other purpose, it has become customary to use an incandescent lamp connected by flexible cables to a plug inserted instead of the lamfp in one of the lamp-sockets on the automo- These sockets, according to the prevailing economical practice, are commonly installed on a single-wire grounded circuit; that is to say, a circuit in which one terminal of the battery or generator is grounded through the metal chassis to the casings of rthe sockets, and in which the other terminal is connected by insulated wires to springpressed contact plungers mounted 1n the respective socket casin s and each insulated from the casing whicli houses the same. ln making a detachable wire-terminal plug for making the desired electrical connection to such a socket, it is easy to provide the connection for the contact lun er, but more diiiicult to provide that or tie wire which is to be electrically grounded to the casing. For the latter purpose, it has been customary to equip, the plug itself with a metal shell or collar, and to solder one of the wires tions by providing a construction which .rc-

quires no collar and hence is less expensive, and by providing wire terminals in which each wire may readily be clamped by screws. Speaking more generally, our invention also aims to provide a simple and inexpensive connector portion for detachably connecting `two relatively insulated conductors to a grounded socket. shell and a conductor housed oy the shell, for utilizing the interlockmg pin as part of the electrical connection, Jfor securing the metal arts to the inf sula'tor with a minimum o fastening elements, for guarding against a short-circuit within the plug, and for effectively concealing the interior construction so as to afford a handsome and compact appearance. Still other obj ects will appear from the following specification and from the accompanying drawings, in which- Figure l is a perspective View of a wireterminal plug embodying our invention.

Fig. 2 is an enlarged central and longitudinal section through `the same, taken vertically through Fig. l.

Fig. 3 is a transverse. section through Fig. 2, taken along the line 3-3 and looking upward.

4 is a longitudinal section through a plug portion showing an alternative method of securing certain of the metal conducting elements to each other.

Fig. 5 is an end view of the plug with all metal parts except the anchoring pin reinsulator, thus affording an approximately oval recess at this end as shown in Fig. 5. Extending transversely through the insulator at right angles to a plane through the axes of the two tubular bores and through the said enlarged recess is a metal pin 3, which is anchored in the rubber of the insulator. This pin extends at both ends beyond the insulator, so as to aford projections disposed for interlocking with bayonet slots on a socket shell 4 after the manner familiar to users of automobile lamp sockets. Within one of the longitudinal bores in the lnsulator we mount a wire terminal 5 and solder this terminal to the pin 3, the latter preferably having its central portion knurled to afford a good hold for the solder. Like lwise, we mount a somewhat longer wire terminal 6 in the other cylindrical bore portion, and thereafter secure this terminal 6 to a contact plate 7 extending beyond the axis of the insulator 1. For the latter purpose, we desirably equip the terminal 6 with a reduced end adapted to enter a perforation in the contact plate 7 and affording an adjacent shoulder against which this plate may abut as shown in Fig. 2. Then the reduced end of the said terminal can be riveted over and may also be soldered tothe contact plate, though we preferably punch the latter of a contour snugly fitting the said enlarged vrecess portion of the insulator bore, so that the Walls of this recess will prevent any lateral movement of the contact plate.

Each of the wire terminals 5 and 6 is desirably held in the insulator merelyby a screw extending transversely through an adjacent portion of the insulator, this being the screw which also fastens the wire or cable in the same terminal (such as the screws 8 and 9 of Fig. 5), so that these screws effectively hold all of the metal conducting parts (except the anchoring pin) in position. To prevent a possible short-circuiting within the plug through any looseness of iit, or bending of the metal parts, or lumping of the solder, we also preferably undercut the longer terminal 6 just beyond the said shoulder so as to give this terminal a reduced shank 10 having an enlarged ring 11 spaced from its lower end. The resulting contraction in diameter affords added clearance between the cross-pin 3 and the portion of the terminal 6 adjacent thereto, and the inner face of the annular enlargement 11 also affords a shoulder for a sheet of insulating material 12 which we preferably slip into the position shown in Fig. 2 before inserting the contact plate 7.

It will be obvious from the above that the anchoring pin 3 will form the electrical connection from the shell 4 to the shorter Wire terminal 5, thus avoiding the expense of the extra metal collar heretofore used for monete this purpose. Likewise, the contact plate 'i' t5 the screws 8 and 9, so that the wires may be connected to the two terminals by any one able to use a screwdriver. Hence our device affords not only a cheap construction, but also one requiring no skill for using the same.

However, while we have pictured and described our invention in a particular embodiment including a contact plate riveted to one of the terminals, and arranged for clamping the wires by screws, we do not wish to be limited to these or other details of the construction and arrangement here disclosed, it being obvious that the same might be modified in many respects without departing from the spirit of our invention. For example, the contact plate mi ht be bent as shown at 7A in Fig. 4, and so dered into a slot in the wire terminal 6, in which case the latter could be even shorter than the terminal 5.

We claim as our invention:

1. In an attachment plu for a socket, an insulator having a pairo bores extending from one of its ends to a larger boreat its other end, a pair of wire terminals mounted respectively in'the first named bores, a contact plate housed by the larger bore and prevented from lateral movement by the walls of said larger bore, said plate being secured' to one of the wire terminals and insulated from the second wire terminal, a

-member carried by the insulator and dishaving as circuit terminals a casing andk plunger axially disposed therein, an insulator equipped with a bore substantially U- shaped in section longitudinally of the insulator, a pair of wire terminals respectively mounted in the U shanks of the said bore, a contact plate secured to one of the wire terminals 'and disposed in the transverse ortion of the said bore and restrained rom lateral movement by the walls of the said bore portion, said plate a'ording elec vtrical connection with the plunger of the socket, a pin extending transversely of the insulator and electrically connecting the otherwire terminal with the casing of the mensa@ socket, and an auxiliary insulator disposed ing this teminal from the said. pin and for insulating the said pin and the last housing aportion of the auxiliary insulator.

named wire terminal from the Contact plate. Signed at Chicago, llllinois, August 25th,

3. A Wire-terminal plug as per claim 2, in 191'?.V 5 which the Wire terminal to which the con- JULTLUS 0. EllS. A

tact plate is secured has a lateral recess spac- EDWARD J. KNAUFF. 

